`MsiGetSummaryInformation()` and `MsiViewExecute()` should accept null for `hDatabase`/`hView`, respectively.

[mjr4077au]

Actual behavior

The docs say that these values are optional and 0 can be specified. The only way for me to handle this is to create a SafeHandle with a value of nint.Zero and use it.

Expected behavior

That these optional SafeHandle values accept null and handle it internally.

Repro steps

1. NativeMethods.txt content:

MsiGetSummaryInformation
MsiViewExecute

2. NativeMethods.json content (if present): N/A

3. Any of your own code that should be shared? N/A

Context

• CsWin32 version: 0.3.269
• Win32Metadata version (if explicitly set by project): N/A
• Target Framework: net472
• LangVersion (if explicitly set by project): N/A